Shooting hobbyists seeking economy and/or high precision ammunition employ hand loading machines to manufacture their own cartridges from casings, powder, and bullets. A basic loading machine is a press with a frame, and a reciprocating ram that moves toward and away from a die. The base of a metal casing is held by a case- or shell-holder device on the end of the ram, and the case is forced into a die for each of the manufacturing steps such as sizing the case and seating the bullet.
The shell holder has a recess to receive the base of the casing, with the sidewalls of the recess having an undercut groove that closely receives the rim at the base of the cartridge. This secures the case to the ram when it is withdrawn from the die. The recess does not fully encircle the casing, but is open on one side so that cases may be laterally inserted and removed from the recess. The flat floor of the recess extends in a plane to the periphery of the shell holder at the side opening.
The shell holder is secured to the ram by similar means, with a flange or rim on the base of the shell holder engaging a pocket on the face of the ram, with the pocket having an undercut receiving the rim, and a lateral opening to allow lateral insertion and removal of shell holders, which are of different sizes for different cartridge specifications. Thus, the shell holder is robustly secured to the ram against axial forces. However, it is desirable to secure the shell holder to the ram against unintended lateral removal during use. The insertion and removal of cases into the shell holder could dislodge it from the ram, or cause it to be slightly misaligned, resulting in spoiled production.
Accordingly, existing shell holders are retained by a wire spring connected to the ram. The spring generates a moderate force that is adequate to resist inadvertent removal of the shell holder, but limited enough to allow the holder to be removed with deliberate force. While effective, spring retention devices have certain disadvantages. The production of small wire springs is imprecise, with dimensional and strength variations being difficult to eliminate. Cutting of spring wire can generate burrs, which can affect operation if not of a consistent size and orientation on the part. Pre-assembly inspection of springs is required, adding to production time and cost to fabricate a loading machine.
In addition, conventional loading machines require dexterity of the user, including the step of positioning the case in the shell holder. This must be done for each of the several manufacturing steps. The groove into which the case rim must be inserted is small, and requires careful alignment, and may be difficult for the user to see with hands and the machine frame obscuring the user's view of the insertion process. The case must be aligned axially and laterally with the groove, with few useful alignment points of reference to guide insertion.
The present invention overcomes the limitations of the prior art by providing an ammunition manufacturing machine. The machine has a frame with a die receptacle, and a reciprocating ram having a free end movable toward and away from the die receptacle. The free end of the ram receives a removable shell holder having a recess shaped to receive the base of a casing. The recess has a flat floor portion, and the shell holder is removable along a path lateral to the axis of the ram's motion. A retention ring removably encompasses at least part of the shell holder and of the free end of the ram, so that the shell holder is secured by the retention element against lateral removal. The retention element may have a flat upper surface aligned with the floor of the shell holder recess, to provide a guide for sliding the case into the shell holder. The retention element may also have an internal O-ring that compressibly surrounds the end of the ram, to provide a friction fit and allow for variations of size of the ram, holds and centers the retaining element on the ram.